Referring to FIG. 1A, the prior art U.S. Pat. No. 4,298,243 shows an electrical connector for connecting two kinds of electrical conducting terminals. There is only one conducting element 6A located inside the insulating housing 8A. The conducting element 6A connects a flat-type conducting terminal to a conducting core. Wherein the conducting core is directly inserted into the cylindrical crimp ferrule 14A at the end of the conducting element 6A. An external clamping force is then exerted to deform the cylindrical crimp ferrule 14A to fasten the conducting core; therefore, the connecting force between the conducting core and the conducting element 6A is weak. Meanwhile, the conducting element 6A sticks out and inserts into the insulating housing 8A by an inverting hook 12A; consequently, it is inconvenient for the overall assembly of the connector.
Referring to FIGS. 1B and 1C, another example of the prior art shown in U.S. Pat. No. 5,203,726 is an electrical terminal connector capable of connecting two kinds of terminals. Besides the metallic terminal 14B (FIG. 1B), a crimp portion 16C (FIG. 1C) is introduced to connect the conducting core for increasing the connecting force of the conducting core and the metallic terminal 14B. When assembling the connector, the front part 44C of crimp portion 16C surrounds the crimping end 30B of the metallic terminal 14B from a breach 50B and props up the ramp 40B tightly. The stress concentration also occurs near the intersection of the breach 50B and the ramp 40B to reduce the combining strength of the metallic terminal and the crimp portion 16C.
Referring to FIG. 1D, another example of the prior art shown in U.S. Pat. No. 6,997,746 shows a conducting element 50D connecting to two electrical terminals. In order to connect the conducting core without any additional cylindrical crimp ferrule, the structure of the conducting element 50D is very complicated and not easy to fabricate.